runner: combine stdout/stderr via redirect_stderr=True rather than manually
runner: combine stdout/stderr via redirect_stderr=True rather than manually

pv/asv,spacetelescope/asv,pv/asv,airspeed-velocity/asv,spacetelescope/asv,qwhelan/asv,qwhelan/asv,pv/asv,spacetelescope/asv,airspeed-velocity/asv,qwhelan/asv,airspeed-velocity/asv,qwhelan/asv,airspeed-velocity/asv,spacetelescope/asv,pv/asv